The present invention relates to electric submersible pumps. In particular, the present invention relates to electric submersible pumps having improved vibrational characteristics relative to conventional electric submersible pumps.
Electric submersible pumps are used in a variety of situations in which the pump itself is immersed in the working fluid to be moved by the pump. Such is the case in geothermal wells in which hot water is pumped from a geothermal field, frequently far beneath the surface of the earth, through a well bore to a thermal energy harvesting system at the surface.
Electric submersible pumps are widely used in hydrocarbon production operations. Typically, an electric submersible pump is inserted through a well bore into a hydrocarbon reservoir. Hydrocarbon-containing fluid from the reservoir enters the well bore and immerses the electric submersible pump. As the hydrocarbon-containing fluid around the electric submersible pump is drawn into the pump and propelled toward the surface for refining and use, additional fluid enters the well bore from the reservoir.
In both geothermal and hydrocarbon production operations, reliability of the electric submersible pumps employed is essential to success of the operation as replacement and repair options for installed electric submersible pumps in such operations are both limited and unattractive.
It is believed that the vibrational characteristics of a given piece of high speed rotating equipment can play a key role in the reliability and useful life of such equipment. Thus, there have been concerted efforts to discover means of improving the vibrational characteristics of high speed rotating equipment such as electric submersible pumps. Notwithstanding the considerable improvements made to date with respect to the vibrational characteristics of electric submersible pumps, further improvements are needed in order to enable greater efficiency in energy production.